Date: Tue, 2 Aug 2005 13:42:30 -0700 (PDT) From: dpk <dpk@dpk.net> To: freebsd-stable@freebsd.org Subject: Kernel debugging, 5.4-RELEASE Message-ID: <20050802133920.J64406@shared10.hosting.flyingcroc.net>
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What method do kernel developers employ to debug kernel panics? The gdb that comes with 5.4-RELEASE does not have kernel debugging support and the handbook appears to be out of date with regards to KDB. I'm trying to use another gdb, out of ports, that has kernel debugging support but I'm getting the following results: /usr/ports/devel/gdb6/work/gdb+dejagnu-20040810/gdb/gdb -k kernel.debug GNU gdb 20040810 [GDB v6.x for FreeBSD] Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-portbld-freebsd5.4"... (kgdb) target remote /dev/cuaa0 Remote debugging using /dev/cuaa0 0xc035646c in kdb_enter () warning: Unable to find dynamic linker breakpoint function. GDB will be unable to debug shared library initializers and track explicitly loaded dynamic code. warning: shared library handler failed to enable breakpoint (kgdb) bt #0 0xc035646c in kdb_enter () #1 0xc033ea1f in panic () #2 0xc0333181 in lockmgr () #3 0xc038b08b in vop_stdunlock () #4 0xc038af3b in vop_defaultop () #5 0xc03010bb in spec_vnoperate () #6 0xc0301648 in spec_write () etc IE, it's not giving me any argument information. The target machine was booted with kernel.debug, an unstripped kernel built with -g. What additional steps do the kernel developers take to get the arguments? (Unfortunately I cannot get this machine to dump core to swap, so it has to be done over remote)
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